JP2010522824A - Melt metallurgy process for the production of metal melts and transition metal-containing additive materials used therefor - Google Patents

Abstract

  A method of melting a metal melt containing at least one base metal and at least one additional alloy component in the presence of a slag covering the metal melt inside a melting vessel. In order to enrich the alloy component of the metal melt, 5 to 10% by weight of the alloy component, 5 to 10% by weight of volatile components harmless on the melt metallurgy, 5% by weight or less of sulfur, and other alloy components An alloy component-containing additive material containing at least one of the slag generating material is supplied to the metal melt. This additive material is obtained in the form of hydroxide and / or carbonate by leaching treatment from ore and precipitation. The invention further relates to such additive materials.

Description

  The present invention relates to a melt metallurgy method in which a metal melt containing at least one base metal and at least one additional alloy component is melted in the presence of a slag covering the metal melt inside a melting vessel. The present invention also provides transition metal-containing additive materials in the form of solids for use in such melt metallurgy processes, particularly nickel and / or cobalt containing additives for producing alloys containing nickel and / or cobalt. Also related to materials.

  In order to melt an iron alloy or steel enriched with a specific alloy component, in most cases, the composition can be adjusted by adding the alloy component to the molten metal of the raw metal. As this kind of alloy component, nickel, cobalt, vanadium, molybdenum and the like can be added. In order to adjust the composition, iron alloys such as ferronickel and ferrocobalt are often used, but oxide-based components such as nickel oxide and ore such as laterite having an appropriate nickel content are also used. . However, the addition of these components has its own disadvantages.

  For example, it takes considerable cost to prepare iron alloy for adjusting the alloy component content with respect to the molten metal, and a large amount of energy consumption is inevitable. In addition, when using oxide-type ore to adjust the composition of the molten metal, impurities containing undesirable trace components (phosphorus, tin, arsenic, etc., and in the case of certain steels, cobalt, molybdenum, etc.) There is a disadvantage that the cost for removing from the ore is inevitably generated. Combining enrichment processes such as flotation does not always remove such impurities to a satisfactory degree. When undesirable components such as phosphorus and sulfur are brought into the melt from this type of ore, unwanted impurity components are removed from the melt, for example, by appropriate slag treatment using different types of slag. The cost for this is further increased. In addition, when ore is added as an additive material to the molten metal, that is, a metal melt, there are other problems, especially various problems related to the dynamic behavior of the molten metal during refining and the degree of seed crystal formation. The reason is that when the ore is used as an additive material, the solid additive material particles themselves do not always dissolve sufficiently rapidly and completely in the metal melt, which has an undesirable effect on the melt metallurgy process. It is. Moreover, when an oxide-based ore is added to the metal melt, the melting of the ore is highly endothermic, which contributes to the energy balance as a negative factor. For this reason, for example, the serious tendency in process engineering and metallurgy may arise, such as the tendency to slag of alloy components, such as chromium, becomes large. In this case, which element slags is almost dependent on the thermal relationship at the time of process execution.

  It is also known that the same problem as described above occurs when an oxide such as nickel oxide is added directly. Moreover, nickel oxide is toxic and carcinogenic and should be avoided.

  In view of the above situation, the main problem of the present invention is that the control of the melt metallurgy process can be simplified, and the metal melt enriched with the alloy components is appropriately covered with slag to perform mass exchange with the slag. The object is to provide a simple and low cost melting method. Another object of the present invention is to provide an additive material that can be used particularly advantageously in such a melt metallurgy process and can be prepared at low cost.

  According to the invention, these problems are solved by the method according to claim 1 and the additive material according to claim 15.

  In the method according to the present invention, an additive material containing an additional alloy component to be enriched and a high content volatile component harmless on the melt metallurgy is used, and this additive material is preferably sulfur. Low content of water or carbonate, and the content of slag-generating materials such as calcium oxide and magnesium oxide is lower than when ores are used. It has the advantage that the amount is high. In this case, in particular, water may be present at least substantially, that is, practically, as water that is chemically bonded in the form of crystal water or hydroxyl group. Such additive materials can be obtained by suitable ore beneficiation, for example, leaching treatment of laterite ores with acid when the additional alloy component is nickel or cobalt. These leaching treatments may be repeated as necessary to separate and remove other undesired components, and in some cases, the required alloy components may be precipitated and separated from the leaching solution obtained by the leaching treatment. These precipitates may be separated and dried in the next step, in particular, in order to obtain an additive material capable of air current conveyance or gravity conveyance. The additive material thus obtained is calcined or pre-calcined in a separate step as necessary, and the chemicals present in the form of components that volatilize when the additive material is added to the metal melt, such as crystal water. Although it is possible to reduce the bound water, hydroxyl group or carbonate, this is not necessary. It is neither a required alloy component nor a component that volatilizes when the additive material is added to the metal melt, and the content of an undesired component that is not a slag forming material is 15 to 20 weight of the additive material used. %, 5 to 10% by weight, or 2 to 3% by weight.

  Surprisingly, it is possible to use additive materials such as those mentioned above, which contain a high content of components that volatilize when added to the metal melt, in this type of melt metallurgy process, in which case Advantages of being able to melt a high-purity metal melt on the other hand, and the tendency to slag other alloy components is low. The metal melt according to the target alloy application and the production cost of the material produced from the metal melt It has also been found to provide advantages in terms of melting metallurgy such as low cost. In addition, it has been confirmed that the melt metallurgy process can be controlled in spite of the phenomenon caused by calcination of the added additive material, such as generation of a large amount of water vapor and generation of a large amount of volatile gas such as carbon dioxide. . This is especially true when the additive material is added from above the melting vessel, ie from the slag side. The method according to the invention is particularly suitable for base metals in metal melts, ie when the main alloy component of the melt is iron, or for iron-based solutions in which the metal melt typically contains 10-20% by weight of iron. The present invention is not limited to gold but can be applied to cases where the base metal is a transition metal other than iron. In particular, the method according to the present invention is suitable for melting various alloy steels of low alloy steel, medium alloy steel, and high alloy steel. Such steels have a high carbon content, for example 1.5% by weight or more, with respect to the carbon content of the molten metal to which the additive material is to be added, or with respect to the final product of the individual steelmaking process carried out in the melting vessel, respectively. It is preferable to have a high carbon content such that the carbon content is from .75 to 2% by weight, 2.25 to 2.5% by weight, or 2.75 to 3% by weight. The nickel content of the metal melt obtained after the addition of the nickel-containing additive material is 1.5 to 1.75% by weight, 2 to 2.75% by weight, or 3 to 4% by weight, for example approximately 5% by weight. % Or more. Furthermore, the method according to the present invention can be suitably used for melting Cr—Fe prealloy or Cr—Fe—Ni prealloy, and the chromium content is 30 to 35% by weight, 40 to 45% by weight, or 45 to 50%. In that case, the carbon content in the metal melt or final product at the stage of adding the additive material according to the present invention is 2-3 wt%, 3.5-4 wt%, or 4. The metal melt in this case is preferably made by a converter method. In addition, the carbon content of the molten metal in a general converter steelmaking method is often 8 to 10% by weight. In the process according to the invention, a decarburization reaction of the metal melt takes place in most cases. Therefore, the addition of the additive material when the metal melt is melted by the method according to the present invention is almost always performed during the decarburization process by the blowing lance, during the refining process, or directly preceding or following them.

  Typically, the addition of additive material in the process according to the invention is preferably carried out during the main stage of the decarburization process in the steelmaking process or the melting process of the target alloy. Therefore, in the method according to the present invention, it is preferable to supply the additive material to be used in a metal melt that has not yet been decarburized. It does not matter if it occurs.

  The additive material according to the invention, which will form an alloy, may be introduced above the melting vessel or converter upper space, i.e. above the surface covered with the slag of the metal melt in the melting vessel or converter. I like it. In that case, the outlet of the feeding device for the additive material is spaced upward from the slag surface so that the additive material passes through the atmosphere a certain distance before reaching the surface of the slag and thus the surface of the metal melt. Preferably it is.

  The additive material is in the form of a solid, and is preferably supplied directly into the metal melt while forming a combustion spot on the exposed surface of the metal melt itself that has been slag displaced by being blown by air flow. This is particularly important in the case of additive materials containing at least one of nickel or cobalt, but may also be important in the case of additive materials containing other transition metals, particularly vanadium or molybdenum. In this case, since the slag is completely eliminated by the air flow at the metal melt combustion spot (exposed surface of the molten pool) formed at the location where the conveying air current hits, when being supplied into the metal melt from the outlet of the supply device Taking into account the calcination of the additive material, the additive material can be in direct contact with the metal melt without having to pierce the slag layer by itself. Further, in this case, as to the metallurgical change of the additive material and the alloy, generally, the temperature at which the combustion spot is as high as possible, for example, 1750 to 1800 ° C., preferably 2000 to 2200 ° C. or 2400 to 2500 ° C., particularly preferably 2600 It has been found to be advantageous when it has a temperature of ℃ or higher. A very high combustion spot temperature (i.e. the temperature of the metal melt in the combustion spot) results in a very rapid uptake of alloy components from the additive material in the metal melt.

  The calcination of the additive material is controlled in particular so that calcination takes place during or shortly after discharge from the supply device in the form of a lance, in particular by the conveying speed of the additive material towards the metal melt. In this case, some or nearly all of the calcination may occur while the lance is lowered toward the surface of the metal melt, and most or almost all of the calcination is directly within the combustion spot (ie, at the lance). On the surface of the metal melt exposed by blowing airflow from the nozzle outlet), or in a region where the supplied additive material collides with the molten pool and the metal melt forms a depression. It may occur. Thus, the endothermic calcination process of the additive material occurs before the additive material is blown into the metal melt, or alternatively occurs directly in the combustion spot or in the collision zone, thereby causing the additive material to melt into the metal. The additive material will be very finely dispersed while it is already being calcined before being incorporated into the object. Therefore, it can be said that only a very small amount of the calcined gas penetrates into the metal melt, in other words, it does not penetrate at all practically, and it can be said that it does not penetrate at all in the lance, i. Calcination of the additive material in the previous area flowing out of the is avoided. This makes it possible to better manage the overall energy economy of the smelting process, which naturally has special advantages in process execution, in particular the introduction of crystal seeds by calcination of the additive material, so that the metal melt It is also possible to obtain the advantage that slagging of certain alloy components, such as chromium, is avoided. This is also the case, for example, when the additive material is blown through a nozzle in a bath inserted in a metal melt under the slag layer.

  The additive material containing the alloy components is preferably fed to the metal melt as a solid stream, which is surrounded by a gas stream. Thereby, a hollow combustion spot is effectively formed in the metal melt, and an interaction between the additive material and the slag, that is, a chemical reaction is avoided. At the same time, it is possible to focus the solids flow or to adjust its diameter by means of the coating gas flow. Furthermore, the depth of penetration of the additive material into the metal melt or the position at which calcination occurs can be controlled independently of the supply flow rate of the solid additive material by coating with a gas flow, It is also possible to avoid leakage of fine powders such as dust from the flow of solids. In addition, leakage of volatile components such as moisture and carbon dioxide generated during calcination is avoided, which is desirable when performing a specific smelting process. Therefore, it is preferable that the region where the solid flow is covered with the coating gas flow, that is, the carrier air flow, is a range extending from the outlet of the supply device, particularly the blowing lance to the combustion spot. Preferably, the supply device (i.e. the lance) is of the cooling, in particular water-cooled type. The coating gas may optionally be the same as the carrier gas that carries the solids stream. The carrier gas is preferably inert to the additive material at least until the additive material flows out of the feeder (lance), or inert under the conditions of the entire process. The carrier gas may be air in some circumstances, but is preferably air with addition of nitrogen or other inert gas, or nitrogen or other inert gas with no mixing. The carrier gas preferably does not have a higher oxygen content than air.

  As is well known, the supply device, that is, the blowing lance, includes a central pipe for supplying a solid flow and a large-diameter annular outer pipe concentrically arranged radially outside the central pipe for supplying a coating gas. Or a plurality of blowing nozzle tubes arranged in a substantially annular shape along the outer periphery of the central tube. The outlets for the solids flow and the coating gas flow may in particular be shaped in the form of Laval nozzles. If a carrier gas is used, the carrier gas flows out of the central tube along with the solids. The blowing lance may be provided with a water cooling jacket.

  In the present invention, the apparatus for supplying (i.e. blowing) the additive material can be implemented in the form of a closed system so as to avoid contact with workers in any form. This is particularly important in the case of additive materials containing nickel. In the air flow conveying system for blowing according to one embodiment, a powdered additive material is charged into a silo via a compressed air conveying system, and the powdered additive material is further supplied via a pressurized tank. That is, it is supplied to the blowing lance. Again, the powdered additive material flowing out of the blowing lance is coated with a gas stream to minimize the loss of additive material.

  By controlling the calcination of the additive material to occur when it flows out of the supply device (lance) or after it flows out (preferably not before the outflow), the exhaust gas rising from inside the melting vessel is discharged. It is also possible to use heat and radiant heat from the molten bath and the melting vessel or the inner wall of the converter for calcination of the additive material.

  Alternatively, in the case of certain melt metallurgical processes, the endothermic effect that occurs during calcination can be used intentionally to lower the bath temperature. For this purpose, in one embodiment, the coating gas or carrier gas containing oxygen is partially or completely replaced with an inert gas. In this case, the highly exothermic decarburization reaction due to the reaction between the oxygen contained in the blown gas stream and the carbon in the metal melt is at least partially suppressed. Of course, the supply of these gas streams is controlled by the temperature control of the metal melt in a given melt metallurgy process. It is also possible to carry out the process in such a manner that it varies from place to place according to the parameters of the metallurgical process. In that case, the oxygen content of the carrier gas or the coating gas can be increased as necessary to reduce the ratio of the inert gas, or vice versa. Thus, the additive material used in the process according to the invention can be supplied to the metal shaft melt typically in the refining stage of the melt metallurgy process, in particular in the main refining stage.

  The coating gas may contain 25 wt% or more, or 50 wt% or more, and even 75 wt% or more oxygen, and in a melt metallurgy process according to certain variant embodiments, 80 wt% or more, It may contain 90% or more, or 95% or more, and even 98% or more by weight of oxygen, and the coating gas may be substantially pure oxygen. The oxygen content of the coating gas can be 95 to 98% by weight, in some cases 80 to 90% by weight, or 60 to 70% by weight, and further 50% by weight or less, or 25% by weight or less. You can also. The oxygen content of the coating gas and the oxygen content of the carrier gas can be adjusted to 10 to 20% by weight or 5% by weight or less, for example, by adjusting using an inert gas. Pure inert gas may be used for the coating gas or carrier gas. The inert gas to be used can be, for example, nitrogen, preferably argon, depending on the conditions of the individual melt metallurgy process. Also, highly endothermic calcination reactions due to the use of additive materials with a high volatile or calcination ratio, as well as lowering the bath temperature, eg volatile calcination products such as water vapor or carbon dioxide, or oxygen According to the method of the present invention, the bath temperature and the combustion spot temperature are controlled by the reaction products produced by calcination such as hydrogen, carbon monoxide and the reduction of the partial pressure of oxygen and reactive organisms in the combustion spot. Therefore, it is possible to avoid mixing inert gas.

  The carrier gas or coating gas is inactive with respect to the intermediate product during calcination, in other words, the carrier gas or coating gas reacts with the intermediate product or its calcination product with little or no reaction. Therefore, it is preferable to have a composition that does not release any reaction heat or practically releases it. Such a gas composition should be maintained especially before the additive material flows out of a supply device such as a lance.

  It is also possible to add another solid substance to the metal melt, if necessary, together with at least one additive material containing at least one additional alloy component. These other solid materials are conventional types such as, for example, iron alloys, calcium compounds and magnesium compounds (such as CaO, MgO, dolomite, etc.) or slag producing materials such as silicates and quartz, etc. The present invention is not limited to these. The content of these other solid substances in the additive material can be 50% by weight or less, preferably 20-25% by weight, more preferably 10-20% by weight, in particular 5-8% by weight, or The content is preferably 2 to 4% by weight. In some cases, the additive material may not contain these other solid substances.

  The solid flow of additive material supplied to the metal melt contains further solid materials and various components such as carbon, solid / liquid or gaseous hydrocarbons, or reducing materials such as ferrosilicon, aluminum, ferroaluminum, etc. You may do it. However, the additive material as an alloy component contains the solid substance and the reducing material at a content of 10% by weight or less, or 5% by weight or less, preferably 2 to 3% by weight, and further 1% by weight or less. It is preferable. The flow of additive material may not contain particulate carbon, hydrocarbons and other reducing components, including gaseous components and coating gas streams contained in the flow. Therefore, the lance used to supply the additive material does not inherently need a function as a burner, but it is not excluded that the lance has a secondary burner function, but in that case a combustion reaction occurs. It should also occur outside the lance.

  When the additive material used contains chemically bound water at a high content rate, the additive material may be processed so as to be compatible with air current conveyance and gravity conveyance. In this case, the content of free water (residual moisture) that is merely physically bonded is 5% by weight or less, preferably 2 to 3% by weight, or 1% by weight or less based on the total weight of the additive material. And However, it is also possible to select another transport technique other than airflow transport or gravity transport for supplying the metal melt.

  The additive material should be 60 to 70% by weight, 75 to 80% by weight, 85 to 90% by weight, or even 95% by weight or more of the total 1) Alloy components necessary for the target alloy application, 2) It can be composed of either a volatile component that does not have harmful properties on melting metallurgy, or 3) a slag generating material.

  The additive material used in the form of a solid material preferably has an average particle size or maximum particle size of 10 mm or less or about 3 to 5 mm, but in some cases, it is further finely crushed to 0.5 to 1 mm. It may be in the form of powder or fine powder having a particle size range of. The additive material may also be in the form of densely agglomerated powder, such as briquettes, pellets, or granules, and these briquettes, pellets, etc., such as water vapor or carbon dioxide produced by a calcination reaction when supplied to a combustion spot. It is a form that is crushed into pieces by the vaporized discharge flow and spontaneously pulverized.

  The method according to the invention can be carried out in particular as an argon oxygen decarburization (AOD) process. As the melting vessel in this case, an argon oxygen decarburization furnace, a cruzo loire-woodeform (CLU) converter, a vacuum oxygen (VOD) converter, or a chromium converter can be used. In some cases, a BOP converter or a Q-BOP converter may be used as the melting container. Moreover, even if it is not the best, the present invention may be applied to a steelmaking process using an electric steelmaking furnace, for example, an arc furnace.

  The alloying component introduced into the metal melt for composition adjustment is up to 5 to 10% by weight, or 20 to 25% by weight, 30 to 35% by weight, or 40 to 50% by weight through the additive material according to the present invention. This additive material can contain chemically bound water or a calcined component at a high content at the same time. If necessary, it is also possible to supply more than 75% by weight or almost 100% by weight of alloy components to the metal melt via the additive material according to the invention.

  Depending on the size of the melting vessel or converter, the flow rate of the solid flow of the additive material is 100 kg / min or more, preferably 200 to 500 kg / min, with respect to the weight of the metal part excluding the slag of the metal melt. This may be reached (for each heavier molten metal weight).

  Although it has been confirmed that supplying an additive material having a high water content according to the method of the present invention is particularly suitable for an additive material containing nickel or cobalt, the present invention is not limited to this. Therefore, although the embodiments described later relate mainly to nickel-containing additive materials, unless otherwise indicated, the present invention is also applied to additive materials containing cobalt-containing additive materials and other main alloy components such as manganese, molybdenum, or chromium. It should be understood that the effects of the invention apply as well.

  Therefore, the additive material to be used in the method according to the present invention can be obtained from appropriate raw materials such as ore, appropriately ore-treated ore, or various metal products generally containing the desired alloy components and waste thereof. It is possible to obtain by melting or leaching the alloy components, particularly transition metals. These target alloy components to be enriched are converted into a state dissolved in an aqueous solution of acid and the like, and then used as an appropriate agent, for example, a basic agent such as MgO, CaO, or dolomite (in some cases, used as a suspension. Can also be precipitated with ammonia, ammonium salts, or carbonates. Precipitation can be carried out under heating or at room temperature, depending on the treatment method, and in exceptional cases may be carried out under cooling. Thereby, the precipitate formed can be a substantially water-containing hydroxide, carbonate, or a mixture of hydroxide and carbonate. Precipitation of the transition metal constituting the alloy component generally does not use a sulfur-containing precipitating agent, or is performed under conditions where there is no agent that causes sulfur uptake in the resulting precipitate. Therefore, usually the precipitate of the alloy component is separated from the alloy component during the calcination reaction when most or substantially all of the resulting additive material is fed into the upper space of the melting vessel. It is composed of only volatile components such as water vapor and carbon dioxide, which are harmless to melt metallurgy than sulfur-containing gases such as sulfurous acid gas, and components that only liberate slag generating material components.

In this case, the alloy component-containing solution obtained after dissolution or leaching of ore or other suitable material may be purified to remove specific components such as impurities. Moreover, it is needless to say that the transition metal obtained from the raw material can be enriched by, for example, an extraction process, although it is not preferable.

  In a preferred embodiment of the present invention, the additive material is optionally dried to allow air or gravity transport following the dissolution or leaching process. For air current transportation or gravity transportation, the additive material preferably has a residual water content of 5% by weight or less, preferably 1 to 3% by weight, based on free water that is merely physically bonded. It will be appreciated that this residual moisture adjustment by drying is dependent on the individual process conditions.

  The additive material that can be used immediately is 10 to 15% by weight, 15 to 20% by weight, or 25 to 30% by weight of volatile components such as water and carbon dioxide that are volatile and harmless on melting metallurgy during calcination. You may contain by content rate, for example, you may contain by 30 to 35 weight% or 35 to 40 weight% of content rate. The content of the volatile component is preferably in the range of 65 to 70% by weight, for example, 60 to 65% by weight, 55 to 60% by weight, or 55 to 60% by weight. In this case, chemically bonded water can be present in the additive material, particularly in the form of crystal water or hydroxyl groups. If appropriate, the additive material may be pre-calcined to remove some of the chemically bound water, but such a step is not essential. What has been described here is generally true in various cases within the scope of the present invention.

  It is particularly preferable that the essential metal component of the additive material, that is, the main component whose content in the metal melt is to be enriched is at least one or more transition metals. One or more transition metals having the highest content may be 25 to 30% by weight or 40 to 50% by weight based on the total metal content of the additive material alone or in total depending on the individual alloy application, preferably It may be present at a content of 60 to 70% by weight, provided that the total amount of metal in this case includes iron and slag-generating metals such as calcium and magnesium. The transition metal or metals are preferably oxides that can be reduced when in contact with the metal melt under the conditions of carrying out the process according to the invention or after being fed into the metal melt, so that These transition metals are transferred into the metal melt in the form of metals by a melt metallurgical reaction with the metal melt. Accordingly, the metal melt acts on the transition metal oxide formed by calcination of the additive material, or, in some cases, acts reductively on the additive material itself. In addition, transition metals present in oxide and metal forms have a vapor pressure that is not too high, i.e. not a problem in melt metallurgy, thereby avoiding loss due to vaporization of metals and metal oxides. It is preferred that it be kept or kept insignificant. This loss includes a loss due to the accompanying metal oxide or the material of the additive material itself due to leakage of the calcined gas. A substantial component of the additive material, i.e., the main component, is one or more transition metals such as Ni, Co, V, Mo, Mn, Cr, Ti, Zr, W, Nb, Ta, or combinations thereof. Well, however, the transition metal is preferably Ni, Co, Mo or V, in particular Ni or Mo. In some cases, Ni and Co may exist in combination, and in that case, either Ni or Co may be the main component.

  For the preparation of the additive material containing nickel or cobalt, it is advantageous to use a leached product of laterite ore or a laterite-like ore (for example, saprolite). However, it is particularly preferred to use laterite, the most advanced weathering product. Laterite nickel ore contains about 1-2% by weight of nickel bound to goethite, bound to nickel limonite with a very high iron content and silicates, especially serpentine, A distinction is often made between nickel silicate ores which often contain more than 2% by weight of nickel. It goes without saying that other sources, in particular ores, should be used in the case of other transition metals.

  For the leaching of nickel or cobalt, an acid, for example sulfuric acid, can be used. The leaching process is preferably performed by deposition leaching. This leaching treatment is generally performed under atmospheric pressure, and in some cases under pressure (for example, high pressure acid leaching). Of course, other leaching methods such as biological leaching processes, ammonia / ammonium leaching methods, etc. can be used. This is also true for various transition metals generally obtained from ores or other raw materials. The leaching treatment is preferably performed without using sulfides or hydrochlorides. This is also true for various other processes for preparing additive materials.

  Cobalt can be separated from the resulting solution, ie the leachate, in advance by a suitable method using a suitable complexing agent such as phosphonic acid. This can be used for the separation of undesired components other than the purpose, such as alloy components that are undesired for the purpose, and can generally be used for the preparation of additive materials containing other transition metals such as nickel. is there. In particular, nickel and cobalt can be co-precipitated one after another to obtain a so-called mixed precipitate (MHP). This is true for other mixed transition metal precipitates as well.

  The nickel content of the nickel-containing additive material is 5 to 10% by weight, 15 to 17% by weight, or 20 to 23% by weight, and in some cases 25 to 27% by weight (residual moisture for those having a residual moisture of approximately 0% by weight) Content). The nickel content is typically 50-55% by weight, alternatively 40-45% by weight, and in some cases about 60-65% by weight or even higher. These descriptions relate to additive materials used in the melt metallurgy process, but the same applies to cobalt-containing additive materials or additive materials containing transition metals belonging to other first transition metal periods such as vanadium ( This also applies to mixed additive materials such as nickel / cobalt containing additive materials containing two or more alloy components. In that case, for a transition metal having a second period or more, such as molybdenum, if the ratio between the atomic weight of the transition metal having the second period or more and that of a first period transition metal such as nickel is taken into consideration, The same is true.

  The following description relates specifically to Ni / Co-containing additive materials obtained by leaching of laterite ore, but this description is also generally applicable within the scope of the present invention.

  The additive material is 5 to 10% by weight, or 11% by weight or less, or 15 to 21% by weight, or 25 to 30% by weight or 35% by weight of water chemically bonded in the form of crystal water or hydroxyl group. It can be contained in a content of ˜40% by weight, which is generally true for all additive materials that can be used within the scope of the present invention. Preferably, the additive material contains an amount of water (including chemically combined water) not exceeding 50-55 wt%, or 60-65 wt%. When the additive material is carbonate or a mixture of hydroxide and carbonate, the contents corresponding to the above contents are applicable to carbon dioxide and chemically combined water.

  The sulfur content of the additive material is preferably 5 to 10% by weight, in particular 4% by weight or less, ie 2-3% by weight. The sulfur content is more preferably 0.5 to 1% by weight, or 0.2 to 0.3% by weight. The same applies to the chlorine content, which is generally true within the scope of the present invention.

  When the additive material is used only for alloying nickel, vanadium, and molybdenum in the metal melt, the cobalt content is 2.5-2% by weight, 1.75-1.5% by weight. Or in the range of 1.25 to 1% by weight. This is particularly true when the additive material is utilized for alloying nickel, for example when Ni is present as the main component. Thus, the cobalt content is not an issue for other cobalt sources of the metal melt, and as such, with respect to the amount of additive material that can be used in the melt metallurgy process in individual alloy applications, the cobalt content is undesirably high. There are no restrictions to avoid the amount.

  In order to prevent the amount of phosphorus, copper, tin, lead, niobium, arsenic, cadmium or lead contained in the additive material from exceeding the upper limit of these components contained in the metal melt, It is preferred that the amount of additive material added to the metal melt in the melt metallurgy process in alloy applications is kept to an insignificant amount. In the case of alloying only nickel with additive material, the same restriction applies to components such as cobalt, vanadium, and molybdenum, and vice versa. By preparing the additive material from an aqueous solution of the required transition metal depending on the specific alloy application, the content of these components can be controlled relatively easily by known methods.

  In addition to the main alloy component, for example, cobalt (in the case of nickel-containing additive material), nickel (in the case of cobalt-containing additive material), or other alloy components such as manganese, these elements are used for individual alloys. Can be included as long as it is not desired or disturbed. In the case of an additive material containing nickel or cobalt obtained by leaching treatment of laterite, manganese (for example, 0.25 to 5% by weight, or 1 to 2% by weight) may further be contained. The manganese content may be 7.5 to 10% by weight or 5% by weight or less, and the cobalt content may be 0.1 to 0.25% by weight or 0.75% by weight or less. In this case, the cobalt content can be 3 to 5% by weight or 2% by weight or less. In this case, the content of the alloy component containing iron is 1 to 2% by weight, or 3% or less, 15% by weight or less, 10 to 12% by weight, or even 8 to 10% by weight. . This is generally true within the scope of the present invention.

  The additive material may further contain a slag generating material such as calcium, magnesium and the like. The content of the slag generating material in the additive material, for example, the content of calcium or magnesium, is 0.5 to 1% by weight or 1.5 to 2% by weight as the weight of the metal element for the additive material excluding residual moisture, respectively. %, Or 3 to 5% by weight. Slag generating materials, such as Ca and Mg, may be present in a form suitable for the melt metallurgy process, such as oxides, hydroxides, carbonates or silicates. The content of the slag generating material should be 25% by weight or less, or 15 to 20% by weight, especially 10 to 12% by weight, or 6 to 8% by weight of the additive material (excluding residual moisture) to be used in the process. Can do. These content values may be interpreted as values including at least one of Mn, Cr, Si, Ti, Si, and Fe, and may be interpreted as values excluding these. The above description is generally applicable within the scope of the present invention.

It is a schematic cross section which shows the principal part of the apparatus for enforcing the method by this invention.

  Hereinafter, an embodiment of the present invention will be described in detail. The attached drawing is a schematic cross-sectional view showing a melting vessel (converter) equipped with an additive material supply device in the form of a lance.

  FIG. 1 shows an example of an apparatus for carrying out the method of the present invention, in which a metal melt 2 whose surface is covered with a slag 3 is refined in a melting vessel 1 in the form of a converter, for example. The metal melt is an iron alloy, for example a nickel alloy steel with a nickel content of 1.5 to 30% by weight, in particular a chromium nickel alloy steel such as ordinary nickel steel or 18/8 chromium nickel steel, or a phosphorus and sulfur content. Are iron alloys for making steels of less than 0.005% by weight and less than 0.0035% by weight, respectively (this is true regardless of this example). In this case, the slag contains a high content of conventional slag for producing alloys for individual purposes, such as chromium oxide, MgO, CaO, silicon, not only covering the surface of the metal melt, It can also participate in metallurgical reactions of objects.

  The feeding device for introducing the additive material into the melt comprises a lance 4 which is spaced above the slag surface and is preferably water-cooled. The lance enters the upper space of the melting container 1, and the nozzle opening at the lower end faces the slag surface with an interval therebetween. The lance 4 has a center tube 5 for blowing the additive material in the form of a solid, and a plurality of, for example, 2 to 3, or 4 to 4 are provided on the outer peripheral surface of the center tube so as to surround the periphery of the center tube. Six or more outer tubes 6 are attached in an annular arrangement. The lower end opening of each tube is equipped with, for example, a Laval nozzle type blowing nozzle so that the additive material can be blown into the metal melt, preferably at a speed exceeding the speed of sound. Therefore, the air-carryable additive material consisting of solid particles is blown into the metal melt through the central tube using a suitable carrier gas such as oxygen, and at the same time the coating gas stream is passed through the outer tube 6 into the metal melt. The coating gas flow covers the outer periphery of the flow of solids blown out from the central tube 5 to form a focused flow. In this case, the coating gas stream 7 firstly physically protects the solid stream 8 from the surroundings, taking into account the large amount of volatile components generated especially during the calcination of the additive material. It is used to focus the entire flow, including the flow, so as not to diffuse. In particular, the coating gas flow also serves to cause the appearance of a combustion spot 9 consisting of a depression of the metal melt that penetrates at least the most, preferably the entire thickness, of the slag layer and is not covered by the slag. . Therefore, the surface of the metal melt 2 is exposed at the combustion spot. In this case, the temperature of the metal melt in the region of the combustion spot reaches, for example, 2400 to 2600 ° C.

  In the present embodiment, the additive material is such that the calcination reaction occurs with the separation of moisture, carbon dioxide and possibly other volatile components, and immediately after the additive material exits the lance nozzle outlet. Infused. In this case, decomposition of the additive material by calcination is caused by a large part or the whole of the interval from the lance nozzle 4a to the molten pool due to the surrounding high temperature state (for example, the melting container wall 1a, radiant heat from the metal melt, etc.). Done in If the additive material has an uncalcined portion, it is completely calcined in the combustion spot 9 of the metal melt or in the collision zone 10. For this reason, all volatile components such as moisture and carbon dioxide are vaporized during calcination, and only non-volatile components such as metal oxides enter the metal melt and are taken into the metal melt. Become.

  The carrier gas guided along with the solid flow through the central tube 5 may be air, oxygen-enriched air, or an inert gas. The coating gas introduced through the outer tube 6 may be air, oxygen-enriched air, pure oxygen, or an inert gas, or a mixed gas thereof. It is desirable that the oxygen content of these gases be adjusted in accordance with the melt metallurgical process conditions according to individual alloy applications, the thermal economy of the melt metallurgical process, and the like. In some cases, a flow of alloy components, slag formers, or other similar solid additives may be supplied to the metal melt along with the flow of additive material, but this is not necessary. The additive material stream preferably does not contain carbon, ferrosilicon, aluminum, or similar reducing agents. The method according to the invention may in particular be an AOD process but in some cases an electrorefining process.

  According to the present inventors, it is possible to supply an additive material for adjusting the alloy content of the metal melt even if a substance with a high water content due to chemically bonded water is used as the additive material. In particular, thereby enabling the additive material to be prepared at an advantageous cost and avoiding other costly processes such as slagging to reduce the sulfur content of the metal melt, It is possible to significantly reduce the manufacturing cost of the alloy according to the intended use. Performing this type of process is particularly effective by blowing the additive material directly into a very hot combustion spot that is not covered by slag.

  The additive material can be obtained in particular by leaching of laterite, for example by leaching with sulfuric acid at atmospheric pressure or under pressure, but depending on the case, other leaching methods may also be used. From the acidic leachate obtained by leaching treatment, by adding carbonates such as sodium carbonate, calcium carbonate, dolomite, or ammonia or ammonium compounds, nickel hydroxide, nickel carbonate or nickel hydroxide / nickel carbonate mixture is essentially added. And the nickel-containing additive material can be precipitated with a precipitating agent such as a suspension of MgO or CaO. The reaction with the precipitating agent is performed at a high temperature (for example, 30 to 80 ° C. or even higher temperature) for an appropriate time, for example, several minutes to 1 hour. In some cases, it is also possible to separate the cobalt in a suitable manner such as an extraction process in a separate preceding step.

  The additive material may be dried in advance until it has a residual moisture concentration that allows its own air flow. In this case, the residual moisture is simply regarded as physically bonded (attached) water, and this moisture can be removed by drying at 120 to 150 ° C. for an appropriate time (for example, 1 to 2 hours). Appropriate pretreatment can be applied to the additive material so that gravity transfer can be suitably performed.

  The additive material may be mechanically pulverized so as to have an appropriate particle size or particle size, or may be compacted by compression and densification, or may be aggregated and granulated.

  In the case of nickel-containing additive materials, the nickel content is typically about 15-55% by weight, especially 20-40% by weight, based on the pre-dried additive material (without residual moisture). . The content of water chemically bonded in the form of crystal water or hydroxyl group is typically 30 to 50% by weight, or 40 to 50% by weight. In some cases, the additive material may be pre-calcined to reduce the moisture and carbonate content, but this is not necessary.

  Below, typical analysis results of two nickel-containing additive materials are shown. These products were each leached with 90% sulfuric acid at 90 ° C. for 0.5 hours (about 20 g of ore was leached with 80 g of water and 100 g of sulfuric acid). It has been found that the leaching treatment time is advantageously less than 1 hour or less than 0.75 hour. The leachate was partially neutralized with dolomite and then reacted with the MgO suspension to precipitate nickel hydroxide.

  The precipitate was filtered off and dried (at 120 ° C. for 2 hours) until the residual moisture was about 1.5% by weight. The content of chemically bound water is 45% by weight per dry matter with a residual water content of about 0% by weight calculated from the weight loss after thermal decomposition at 750 ° C for 4 hours until the weight becomes constant (composition 1) And 45% by weight (composition 2). Thermally decomposed products may still contain some carbonates or other components that will not decompose unless processed at higher temperatures.

  Of course, the composition of the additive material may vary depending on the ore or nickel-containing material used. The analysis results shown below relate to an additive material dried at 120 ° C. for 2 hours to have a residual water content of about 0% by weight (ie, including crystal water).

   It goes without saying that other raw materials other than ores can also be widely used for the preparation of additive materials used according to the present invention. It is possible to prepare additive materials containing nickel or broadly containing transition metals from these raw materials in the same manner, in which case the transition metals are appropriately leached with a leaching solution containing water. It is preferable that it can be taken out by processing.

  Also, the method according to the invention is not limited to the use of additive materials containing nickel or cobalt, but other alloy components, in particular transition metals such as molybdenum, vanadium, etc. are also added to the metal melt in a similar form. Needless to say, this is possible. In this case, it is desirable that the additive material be blown from the upper part of the melting vessel into the extremely hot region of the metal melt in the melting vessel according to the specific target alloy application, and the metal melt in the melting vessel is covered with slag. In the case where it is broken, it is preferable to form a combustion spot free of slag and blow it inward.

Claims (27)

  In the method of melting a metal melt containing at least one base metal and at least one additional alloy component in the presence of slag covering the metal melt inside a melting vessel, the additional alloy component 5 to 10 wt%, 5 to 10 wt% of volatile components harmless on melt metallurgy, 5 wt% or less of sulfur, and an alloy component-containing additive material containing at least one of other alloy components and slag generating materials To the metal melt to enrich the alloy components of the melt.   The alloy component-containing additive material is directly supplied to the metal melt by a gas flow, and at that time, the surface of the metal melt covered with slag is generated while generating a combustion spot free of slag. The method according to 1.   The supply of the alloy component-containing additive material to the metal melt is performed at least after the alloy component-containing additive material substantially flows out from the supply device outlet of the alloy component-containing additive material or in the collision zone on the metal melt. The method according to claim 1, wherein the process is performed such that the alloy component-containing additive material is calcined or decomposed for the first time before or during the incidence.   The method according to any one of claims 1 to 3, wherein the alloy component-containing additive material is supplied to the metal melt as a solid stream coated with a gas stream.   The method according to claim 1, wherein the temperature of the combustion spot is 1750 ° C. or higher.   6. An oxygen gas having an oxygen content of 25% by weight or more or a substantially pure oxygen gas is used as a gas flow covering the periphery of the alloy component-containing additive material. The method described in 1.   As a gas flow covering the periphery of the alloy component-containing additive material, a gas flow containing 75% by weight or more of at least one inert gas, or a gas in which the main component is substantially composed of one or more inert gases The method according to claim 1, wherein a flow is used.   The solid stream containing the alloy component-containing additive material further contains at least one of another alloy component-containing additive, a metallurgically effective substance, and a slag-forming substance. The method according to any one of the above.   The solid stream containing the alloy component-containing additive material contains 10% by weight or less of a reducing agent including carbon, hydrocarbon, and ferrosilicon, according to any one of claims 1 to 8. The method described.   The method according to any one of claims 1 to 9, wherein 5 to 10% by weight of an alloy component constituting the main component of the additive material is supplied to the metal melt by the synthetic component-containing additive material.   The method according to any one of claims 1 to 10, wherein the alloy component-containing additive material contains nickel and / or cobalt as a main alloy component.   The majority of the alloy component-containing additive material is a crystal water-containing salt, a hydroxide, a carbonate, or a mixture of a hydroxide and a carbonate, according to any one of claims 1 to 11. the method of.   70-80% by weight of the alloy component-containing additive material is composed of 1) an alloy component necessary for the target alloy application, 2) a volatile component that does not have harmful properties on melt metallurgy, and 3) a slag generating material. The method according to claim 1, wherein:   14. A method according to any one of the preceding claims carried out as an argon oxygen decarburization (AOD) process.   A transition metal-containing additive material for producing a transition metal-containing alloy by a melt metallurgy method, wherein the transition metal content is 10% by weight or more and is chemically bonded in the form of crystal water and / or hydroxyl group. Including a volatile component content of 10% by weight or more, a sulfur content of 5% by weight or less, an additional alloy component or slag generating material content of 2% by weight or more, and having a solid form A transition metal-containing additive material characterized by   The additive material according to claim 15, wherein the transition metal is nickel, cobalt, vanadium, molybdenum, or a combination of two or more thereof.   The additive material according to claim 16, wherein the transition metal is at least one of nickel and cobalt.   The addition according to any one of claims 15 to 17, wherein the content of at least one or a combination of nickel, cobalt, vanadium and molybdenum in the additive material is 15 to 60 wt%. material.   The additive material according to any one of claims 15 to 18, wherein the content of water chemically bonded in the form of crystal water or a hydroxyl group is 20% by weight or more.   The additive material according to any one of claims 15 to 19, wherein the sulfur content is 2% by weight or less.   The additive material according to any one of claims 15 to 20, wherein the content of the additional alloy component is 3% by weight or more.   The additive material according to any one of claims 15 to 21, wherein the content of the slag generating material is 20% by weight or less.   The additive material according to any one of claims 15 to 22, wherein the additive material has a form capable of air current conveyance or gravity conveyance or a compacted form.   The additive material according to any one of claims 15 to 23, which is obtained by leaching laterite or laterite-like ore with an acid.   The additive material according to any one of claims 15 to 24, which is obtained by precipitating a hydroxide or carbonate from an aqueous solution or a pretreated aqueous solution.   The additive material according to any one of claims 15 to 25, wherein the additive material is made weight invariant by a reduction of 20 to 60% by weight after heat treatment at 750 ° C.   Use of the additive material according to any one of claims 15 to 26 in the method according to any one of claims 1 to 14.

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